Radar is an acronym for Radio Detection And Ranging and was developed in World War II. It’s been used since the 1950’s first with gigantic S band radar gun pictured below the venerable, huge Speedalyzer next to Kustom Signals new Directional Golden Eagle two piece, Ka band radar. Radar guns come in two flavors: handheld or two piece. You see the two piece variety mounted on the dash board of patrol cars. Radar works by bouncing a microwave frequency off a moving object and measuring the difference in the transmitted and returned frequency. This is call Doppler shift. If the retuned frequency is higher than the transmitted frequency called compressed the vehicle is approaching the radar gun. If the returned frequency is lower called stretched the target vehicle is going away from the radar gun. The recent past has seen dramatic improvements in radar technologies. New directional radar only shows vehicles in one direction eliminating 1/2 of the possible mistakes.

     The officer sees the approaching Corvette and not the 18 wheeler going away from the radar gun. New guns offer “fast” modes. Now radar can see and report the speeding Mustang in a group of 18 wheelers. Interfacing the radar to the patrol car’s transmission called VSS, Vehicle Speed Sensor, eliminates low Doppler errors of shadowing and dramatically increases accuracy. Ka band, 33.4-36 GHz is now the frequency of choice. Some 80% of all new radar guns use this frequency. Only New Jersey still uses X band at 10.525 GHz by state contact. Hand held radars are smaller, smarter, and more flexible. They can be hand held or placed in the patrol car and used as a traditional two piece units. Moving radar came in the early 1970’s. A momentary on/off switch was added called “instant on” shortly thereafter. If was introduced to defeat radar detectors. Applied Concepts Inc, i.e. Stalker Radar introduced digital radar guns beginning with their Ka band at 34.7 GHz in 1991. Digital is vastly superior to previous analog radar guns. It measures speed in a 12 inch travel distance of the target vehicle compared to analog radar gun that waited for 10 to 15 car lengths to begin showing speed.

     Laser as a speed enforcement system was introduced by Laser Technologies Inc. in the early 1990’s. Its three milliradian, 904 nanometer, infrared beam could single out individual vehicles in a group. At 500 feet its beam is a mere 18 inches in diameter compared to X band radar at 159 feet. Many metropolitan police agencies have gone exclusively to laser guns as its pinpoint, surgical accuracy carves out one vehicle in rush hour traffic. Honolulu only uses laser, not radar guns. Radar detectors are of no or little use against laser guns. The beam is too narrow for them to see and give any advanced warning. Now, laser can be used through the windshield or in the rain or snow. New laser guns are less than a pound and can fit in your pocket. Both radar and laser guns are approved for emission and eye safety by federal agencies. The International Association of Chiefs of Police publishes its CSP list of approved radar and laser guns. See www.theiacp.org. Laser gun use is increasing. Expect a laser gun to come to a neighborhood near you. Makers are now interfacing digital cameras with laser guns for proof positive of speeding.